JPS60141617A - Manufacture of ferrierite type zeolite - Google Patents

Abstract

PURPOSE:To manufacture titled zeolite having high purity and high SiO2/Al2O3 (by molar ratio) with excellent reproducibility by crystallizing a uniform phase compound of granular amorphous aluminosilicate having a specified composition in a medium such as water. CONSTITUTION:A uniform phase compound of granular amorphous aluminosilicate which contains 3-14wt% (expressed in terms of anhydride) Al2O3 and 1-17wt% (expressed in terms of Na2O, K2O) alkali metal is mixed with water in such proportion that the molar ratio [K<+>/(K<+>+Na<+>)] of potassium ion to metal ion contained in all the reacting mixture is regulated to 0.1-0.9 and the mixture is caused to react in an autoclave while stirring at about 100-300 deg.C to produce ferrierite type zeolite. Further, in said reaction, an aq. soln. of alkali metal hydroxide (NaOH, KOH) wherein said condition is satisfied may be used instead of water.

Description

[Detailed Description of the Invention] It relates to a manufacturing method, and more particularly, it relates to a manufacturing method, and more particularly, to a method for producing S1 with high purity and without using any organic mineralizer or inorganic mineralizer.
02/A120, a method for easily producing ferrierite-type zeolite with a high molar ratio with good reproducibility.

Zeolite is a crystalline aluminosilicate containing zeolite water, as shown by its origin from the Greek word "boiling stone", and its composition is generally expressed by the following formula.

1M2/n0-k]tO,-'j/F310. -211
．． 0 (where n is the valence of the cation M, χ is 0.8 to 2
, where y is a number greater than or equal to 2, and 2 is a number greater than or equal to 0.

) Its basic structure consists of a 5104 tetrahedron with silicon at its center and four oxygen atoms coordinated at its vertices, and an AlO4 tetrahedron with aluminum at its center instead of silicon.
They are regularly bonded three-dimensionally by sharing oxygen with each other so that the atomic ratio of AI+St) is 2.

As a result, a three-dimensional network structure having pores of different sizes and shapes is formed due to the different bonding methods of the tetrahedrons.

Further, the negative charge of the AlO4 tetrahedron is electrically neutralized by bonding with a cation such as an alkali metal or an alkaline earth metal.

Generally, the pores formed in this way range from 2 to 5 A to 1
Although the size of the pores is several A, the size of the pores can be changed by replacing the metal cations bonded to the AlO4 tetrahedra with other metal cations of different size or valence.

Zeolite can be used as a gas or liquid industrial desiccant that utilizes these pores, or as a molecular sieve that adsorbs and separates molecules in a mixture of two or more molecules, and when metal cations are exchanged with hydrogen ions, it can be used as a solid acid. Because of this, it is widely used as an industrial catalyst that takes advantage of this property.

7 Elierite type zeolite also exists in nature, and its typical composition is (N~, Mg)O.Al2O2-11,ISi
O, good is expressed as 65-0. Its crystal structure consists of a skeletal unit of a 5-membered oxygen ring, with a pore consisting of a 10-membered oxygen ring measuring 4.3 x 5.5 A, and an A4 x 4.8 A pore.
It is characterized by having pores consisting of eight-membered oxygen rings.

Various methods for synthesizing ferrierite-type zeolites have been proposed so far, as described below. However, these methods have advantages and disadvantages, and the reality is that no industrially satisfactory method has yet been developed. For example, (1) 0. The method proposed by M. L. and Kibby et al. requires a high temperature of about 300° C. or higher for crystallization, which necessitates the use of a high-temperature, high-pressure reaction vessel. (
Journal of Oatalysig Vol.
55, pp. 256-272 (1974)) (2) The method disclosed in JP-A-51-106,700 can be synthesized at a relatively low temperature. Alumina must be prepared, and the presence of potassium ions in the reaction system is not only essential, but potassium ions can also be added as mineralizing agents in the form of potassium salts of limited organic or inorganic polybasic acids. This is also an important condition. As described above, this method requires complicated selection of raw materials and combination thereof.

(3) The method disclosed in JP-A-50-127.898 and JP-A-55-85,415 uses N-methylpyridine hydroxide and piperidine and/or alkyl-substituted piperidine as an organic mineralizing agent. It is an essential condition that it be used as a.

These organic amines are not only expensive, but also because they are incorporated into the zeolite produced.
When using the ferrierite-type zeolite obtained by this method as an adsorbent or catalyst, the zeolite obtained by synthesis is calcined in the presence of oxygen at a high temperature of 500°C or higher to remove these amines. The removed sample must be used. In order to use the zeolite for specific purposes, it is necessary to pre-treat the zeolite itself.

(4) The method disclosed in JP-A-53-144,500 synthesizes a ferrierite-type zeolite called ZSM-35 using butanediamine or an organic nitrogen-containing cation derived therefrom. However, in this method as well, the synthesized zeolite must be pretreated in the same way as the method (3) above before being used for various purposes.

So far, Mordenai including 7 Elielite)
, ZSM-5 and other zeolites whose zeolite skeleton constituent units are composed of five-membered oxygen rings are relatively SiO2/
Al, 0. Although it is known that a compound with a high molar ratio is produced, the synthesis method adopts a method that requires the addition of an organic nitrogen-containing compound or other organic compound to the reaction system, as described above. It was common for there to be.

Furthermore, in these known methods, particularly expensive aqueous colloidal silica has usually been used as a silica source in order to increase the activity of the reaction mixture.

The inventors have developed M2/110 *l, osSi02 h
, conditions for producing crystalline aluminosilicate zeolite from the o system (n is the valence of the cation M), especially the silica source.

Selection of raw materials including alumina source 1 As a result of intensive research over many years on the preparation conditions of the reaction mixture and the crystallization mechanism of zeolite, we have developed a method that is fundamentally different from the known methods described above. It is. That is, the present invention enables the production of granular particles having a specific composition without using any organic or inorganic mineralizing agents that have been added to the reaction system and without using expensive aqueous co-tetrasilica as a silica source. Amorphous aluminosilicate homogeneous phase compound (hereinafter referred to as
By crystallizing a homogeneous compound (simply referred to as a homogeneous compound) in water or an aqueous alkali metal hydroxide solution, we have completed a method for easily obtaining highly pure 7-elierite zeolite with a high molar ratio of 5to7*4o with good reproducibility. It is something.

The present invention uses inexpensive raw materials without using expensive organic mineralizers to achieve high purity and S i Q2/A 1tOs
The purpose is to provide a method for easily producing 7-elierite-type zeolite with a high molar ratio, and although the conventional method is possible in the laboratory, it is economical from an industrial perspective.

Considering that there are many points in terms of quality, operation, etc., the industrial significance of the present invention is extremely large.

The present invention will be explained in more detail.

The present invention uses aluminum as Al, 03 on an anhydrous basis.
~14wt%, 1-17wt with alkali metal as 40
By crystallizing a homogeneous compound containing 1% in water or an aqueous alkali metal hydroxide solution, a ferrierite type with high purity and high SiOy'A'l, 01% ratio can be obtained without using an organic mineralizer. A method for producing zeolite is provided.

Any method capable of obtaining a homogeneous compound having the composition specified in the present invention can be applied to obtain the homogeneous compound specified in the present invention. For example, it can be obtained by simultaneously and continuously reacting an aqueous alkali metal silicate solution and an aqueous aluminum-containing solution. The present invention will be explained below using this representative example. In the above representative example, the simultaneous and continuous reaction means a mode in which the alkali metal silicate aqueous solution and the aluminum-containing aqueous solution are supplied to the reaction zone simultaneously and while maintaining a substantially constant ratio.

The alkali metal silicate aqueous solution is sodium silicate, potassium silicate, or a mixed aqueous solution thereof. Examples of aluminum-containing aqueous solutions include aqueous solutions of aluminum sulfate, aluminum nitrate, aluminum chloride, sodium aluminate, potassium aluminate, and the like. Further, a caustic alkali or a mineral acid may be added to these as necessary to adjust the amount of the alkali or acid. The rainwater solution may be a commercially available aqueous alkali metal silicate solution, aluminum mineral salt aqueous solution, or alkaline aluminate aqueous solution, or a silica source such as silica sand or hydrated solid silicic acid may be used as a caustic alkali, or aluminum hydroxide or activated alumina may be used as the rainwater solution. It is also possible to prepare an aqueous solution of each aluminum source by dissolving it in a mineral acid or a caustic alkali.

The concentration of the rainwater solution is not particularly limited and can be used at any concentration.

The most preferred embodiment for preparing a homogeneous compound by this method is a method in which a rainwater solution is simultaneously and continuously fed into an overflow type reaction tank equipped with a stirrer under stirring, and the reaction is carried out. This method is effective because the produced homogeneous compound is approximately spherical or in the form of fine particle agglomerates, and most of the particle diameters are distributed in the range of 1 to 500 μm, with only a trace amount of fine particles of 1 μm or less. In the practice of this invention, it is preferred to use homogeneous compounds of 10 to 100 microns. The supply ratio of the rainwater solution is S' 02/h 1.0. It is set based on the molar ratio and can be arbitrarily determined. At this time, the reaction solution suspends the granular homogeneous compound produced by the reaction and becomes a slurry, but the pH of the slurry is adjusted by adding an alkali or acid to the rainwater solution, and usually the pH is
is adjusted to a range of 5 to 9, more preferably a range of 6 to 8. Further, the time the slurry stays in the reaction tank is preferably 6 minutes or more. The residence time here means the time from when the rainwater solution is simultaneously and continuously supplied to the reaction tank until the reaction slurry containing the homogeneous compound produced by the reaction is discharged from the reaction tank. When the residence time is shorter than 3 minutes, the generation rate of fine particles increases. Furthermore, as the proportion of fine particles of 1 μm or less increases, the load on the filtration/separation process of the produced compounds increases, as will be described later, which tends to be undesirable.

On the other hand, when the residence time is 5 minutes or more, most of the product becomes spherical and the presence of fine particles becomes extremely small. Further, as the residence time becomes longer, the particle size increases and at the same time the bond between the particles becomes stronger, and the hardness of the spherical particles increases. Therefore, the length of stay is con).

-The size of spherical particles produced by rolling.

Since the hardness can be changed, the reactivity of the homogeneous compound itself can be adjusted depending on the purpose.

As another example of the embodiment of the present invention, it is of course possible to apply a continuous batch preparation method in which the rainwater solution is simultaneously and continuously supplied at a constant ratio to the reaction tank under stirring conditions without discharging the reaction slurry. However, in this case, it is necessary to supply the rainwater solution over at least 5 minutes, preferably over 30 minutes, without adding it rapidly.

The reaction temperature during the production of a homogeneous compound is not particularly limited, and whether at low or high temperatures, the resulting compound becomes spherical and there is no significant difference in the reactivity of the resulting compound.

What is more distinctive is that by reacting rainwater solutions with adjusted concentrations simultaneously and continuously at a fixed ratio,
Since the composition of the spherical homogeneous compound produced is microscopically uniform regardless of the size of the spherical particles, it is possible to completely prevent the coexistence of impurities caused by the non-uniformity of the composition. .

On the other hand, if one aqueous solution is added to the other aqueous solution, which is the so-called normal batch method, the viscosity of the reaction slurry will increase abnormally, and no matter how strong the stirring is, the resulting slurry will be It is impossible to achieve uniformity. Even if the mixture is sufficiently mixed and appears to be uniform, microscopic non-uniformity in composition cannot be avoided. .

As mentioned above, the homogeneous compound in the present invention has a molecular weight of 1 to 50
Since the spherical particles have a diameter of 0μ, the viscosity of the reaction slurry is very low, and the strong stirring required in the batch method described above is not required, so the concentration of the reaction slurry can be greatly increased.

Since the homogeneous compound obtained by the method of one representative example of the present invention is obtained in the form of spherical objects of appropriate size, solid-liquid separation and washing are extremely easy, which is also one of the features of the present invention. Therefore, solid-liquid separation can be carried out using an ordinary centrifugal separator or vacuum filtration machine, and since it is obtained in the form of a wet cake with very good dehydration properties and low water content, this can be crystallized into ferrierite-type zeolite. A wide range of water balance settings is possible when preparing reaction mixtures for

It is advantageous to use the homogeneous compound after washing in the form of a wet cake, but it is of course possible to use it in dry form.

The method for producing ferrierite-type zeolite in the present invention is a method of crystallization using a mixed ion system of sodium ions and potassium ions, and is further characterized in that it does not use any mineralizing agent containing these ions. When synthesized from a system where only sodium ions exist as cations, the production area is narrow, and the ferrierite type zeolite produced is s j, 07A 1. O, the change in molar ratio is small. Furthermore, relatively high temperatures and long crystallization times are required.

On the other hand, in the method of the present invention in which crystallization is performed using a mixed ion system of sodium ions and potassium ions, the production range is greatly expanded, and the s t O,/A is in the range of 12 to 24 with high purity. , 088 mol of ferrierite type zeolite can be stably obtained. Furthermore, the crystallization temperature is lower and crystallization is completed in a shorter time than in the case of sodium ion systems.

The homogeneous compound obtained by the method of the invention has cation exchange capacity. Another major feature of the present invention is to utilize this property to use a homogeneous ion-exchanged compound as a raw material for the synthesis of ferrierite-type zeolite.

When producing a homogeneous compound, if the only metal cations present in the system are sodium ions, all the cations incorporated into the produced homogeneous compound will be sodium ions, and if the metal cations present in the system are In the case of only potassium ions, all the cations in the generated M-compound are potassium ions. Any of these homogeneous compounds can be used in the practice of this invention. In addition, the cations incorporated in this way can be easily ion-exchanged, such as sodium ions in a homogeneous compound to potassium ions, potassium ions to sodium ions, and even mixed ions of sodium and potassium ions. can do.

Ion exchange can be easily carried out by methods such as immersing a homogeneous compound in an aqueous solution containing sodium and/or potassium ions, and sodium and/or potassium salts of inorganic or organic acids are generally used. . Ion exchange takes place reversibly, and the equilibrium exchange rate is determined by the amount of sodium and/or potassium ions present in the aqueous ion exchange solution and the amount of homogeneous compound used. Another feature is that the ion exchange rate is extremely high.

In carrying out the present invention, it may be advantageous to use an ion-exchanged homogeneous compound since the molar ratio of potassium ions to all cations in the total reaction mixture is limited to a certain range; It can be used effectively.

In general, in order to produce pure zeolite free of impurities, the mixing ratio of each component of the raw materials is very important.

The composition of the homogeneous compound in the present invention is determined by the reaction conditions of the alkali metal silicate aqueous solution and the aluminum-containing aqueous solution used in its preparation, and the conditions of filtration, washing, drying, etc. Furthermore, when ion exchange is performed as necessary, the composition of the homogeneous compound is determined by the conditions of the ion exchange.

The composition of the homogeneous compound used to produce high-purity ferrierite-type zeolite by the method of the present invention is 5 to 14 wt% of aluminum as AI and O on an anhydrous basis.
, containing 1 to 17 wt% of alkali metal as 40, preferably 4 to 12 wt% of aluminum as Al, O, and 1.5 to 1.5 to 1.5 wt% of alkali metal as A and O.
It contains 15 wt%.

Here, the alkali metal is sodium and/or potassium.

If a homogeneous compound with an AI, O, content of 3 wt.% or less on anhydrous basis is used, a large amount of other zeolite as an impurity will coexist, and if the content is 14 wt.% or more, no ferrierite-type zeolite will be produced. Also, those obtained from homogeneous compounds with alkali metal contents outside the above range are undesirable because they contain a large amount of impurities.

The homogeneous compound thus obtained is then heated in water or an aqueous alkali metal hydroxide solution to crystallize it into a ferrierite-type zeolite.

Is it possible to prepare a reaction mixture for crystallization by adding a certain amount of a homogeneous compound of known composition to water or an aqueous alkali metal hydroxide solution, depending on the composition? ), it is necessary to adjust the concentration and amount of the aqueous alkali metal hydroxide solution and the molar ratio of potassium ions to the total -cations contained in the reaction mixture so that the homogeneous compound crystallizes into a high-purity ferrierite-type zeolite. There is.

In the present invention, the aqueous alkali metal hydroxide solution used to crystallize the homogeneous compound is hydroxide.

Potassium hydroxide or a mixed aqueous solution of these. The concentration of these aqueous alkali metal hydroxide solutions is adjusted within the range shown in the following table depending on the aluminum content in the homogeneous compound.

In the method of the present invention, the most preferable conditions for obtaining a ferrierite-type zeolite with high purity and high crystallinity are to satisfy the above range and at the same time maintain a molar ratio expressed in AOH to the silicon component Sin in the homogeneous compound. 0,1~055
, preferably within the range of [L150.5,
In addition, the molar ratio of potassium ions to all cations contained in the reaction mixture is adjusted to a range of 0.9 to 0.9, preferably 0.2 to 0.7.

Further, the amount of water or aqueous alkali metal hydroxide solution is set so that the ratio of the weight of the solid content to the total weight of the starting slurry for crystallization is in the range of 0.04 to 0.4.

As described above, the particle size of the homogeneous compound obtained according to the representative example of the present invention is relatively large and the hardness is also large, so that it does not become fine even under stirring. Therefore, it is possible to reduce the amount of water in the starting slurry without significantly increasing the viscosity of the slurry and within a range where no impurities are generated, making it possible to significantly increase the yield in batch reactions. This is also one of the major features of the present invention.

Crystallization in the present invention is performed by placing a starting slurry for crystallization containing a homogeneous compound in an autoclave at 100 to 300°C.
The temperature is preferably 150°C or higher. During crystallization, it is desirable to stir the autoclave in order to equalize the temperature inside the autoclave.

After crystallization is completed, the generated crystals are separated from the mother liquor, washed with water, and dried to obtain crystal powder. The crystal particles obtained here are granular heptad-type zeolite crystal aggregates with a size of about 1 to 500 μm that maintain the substantially spherical uniform particle shape of the compound.

The ferrierite-type zeolite obtained according to the present invention may be used as an adsorbent or a catalyst after ion exchange with appropriate cations as necessary, in the form of a crystal aggregate, after pulverization, or as a molded body with a binder added. Available.

This will be explained in more detail in Examples below.

<Preparation of homogeneous compound> In an overflow type reaction tank (actual capacity 5.51) equipped with a regular paddle-type stirrer, a sodium silicate aqueous solution with the composition shown in Table 1 and an aluminum sulfate aqueous solution to which sulfuric acid had been added were added. The reactants were fed simultaneously and continuously at a constant feed rate shown in Table 1, and the reaction was carried out under stirring.The apparent residence time of the reaction slurry was as shown in Table 1.

The pH of the slurry is &3~6.61 and the reaction temperature is 50~5.
The temperature was 2°C.

The overflowing slurry product from the reaction tank was subjected to solid-liquid separation using a centrifugal separator, and after thorough washing with water, a wet cake of a homogeneous compound, A-H, having the composition shown in Table 1 was obtained. No SO4: ion was detected in these homogeneous compounds, and all X-ray powder diffraction results showed that they were amorphous.

Next, wet cake O, G of the homogeneous compound prepared as described above is prepared.
and H and an aqueous potassium chloride solution were placed in a 21 separable flask and stirred for 18R at room temperature to perform potassium ion exchange. The amount of homogeneous compound used, the concentration and amount of potassium chloride are shown in Table 2. After completion of the reaction, the resulting slurry was separated into solid and liquid and thoroughly washed with water to obtain homogeneous compound wet cakes E-K having the compositions shown in Table 2. 01 in these homogeneous compounds
No ions were observed, and all X-ray powder diffraction results showed that it was amorphous.

Examples 1 to 7 and Comparative Examples 1 to 3 The wet cake of the homogeneous compound prepared as described above was mixed with an aqueous alkali metal hydroxide solution at 21 or 10 I! The mixture was placed in an autoclave and heated while stirring.

After completion, the resulting slurry was taken out, solid-liquid separated, thoroughly washed with water, and dried at 110°C. The crystallization conditions and results are shown in Table 3. The product was determined by X-ray diffraction pattern. (The powder x!1 diffractogram was measured using the alpha doublet for copper.) Figures 1, 2, and 3 show the results obtained in Example 1, Example 5, and Example 7, respectively. 7 shows a Xi diffraction diagram of elliierite type zeolite.

[Brief explanation of the drawing]

FIG. 1 Powder X-ray diffraction diagram of the 7-elierite type zeolite obtained in Example 1. FIG. 2 Powder X-ray diffraction diagram of the ferrierite-type zeolite obtained in Example 5. Figure 3 Felinyrite-type zeola obtained in Example 7
Powder X-ray diffraction diagram of rt. Patent Applicant: Toyo Soda Kogyo Co., Ltd. Procedural Amendment February 21, 1980 Commissioner of the Patent Office Kazuo Wakasugi 1 Description of the case 1982 Patent Application No. 244798 2 Name of the invention Process for producing ferrierite-type zeolite 6 Telephone number of the person making the amendment (585) 3311 4. Date of the amendment order. 5. Specification subject to the amendment. 6. Contents of the amendment. Type of statement. 7. Attached documents. Type of printed statement. 1 copy.

Claims (1)

[Claims] (11 Aluminum in terms of anhydrous A]-203 is 3
When producing a ferrierite type zeolite by crystallizing a granular amorphous aluminosilicate homogeneous phase compound containing ~14 wt% and 1~17 wt% of alkali metals as A and O (A is Na and/or K), Water or an aqueous alkali metal hydroxide solution (the alkali metal hydroxide is NaOH and / or KOH) and the homogeneous phase compound and crystallizing the mixture. (2) The method according to claim 1, wherein the granular amorphous aluminosilicate homogeneous phase compound is obtained by simultaneously and continuously reacting an aqueous alkali metal silicate solution and an aqueous aluminum-containing solution. (3) The method according to claim 1, which is a single-grain amorphous aluminosilicate homogeneous phase compound ion-exchanged in an aqueous solution containing sodium ions and/or potassium ions. (4) The method according to claim 1, wherein the crystallization temperature is 100 to 300°.